1. Field of the Invention
The present invention relates to an electrostatic attraction apparatus having a pair of conductors arranged electrically separately in an attraction layer or on one side face thereof for attracting and holding a body positioned on the other side face of the attraction layer by an electrostatic attracting force by the DC voltage or the voltage equivalent thereto impressed between conductors of the pair of conductors.
2. Description of the Related Art
Conventionally, in this kind of electrostatic attraction apparatus, detachment is facilitated for an attracted body to be released from an attraction layer by removing the DC voltage or the voltage equivalent thereto, which has been applied between the conductors of a pair of conductors, as is disclosed in Japanese Patent Publication No. Sho. 57-58872(1982).
Even after the DC voltage or the voltage equivalent thereto is removed, the electrostatic charge generated by such a voltage attracts and holds the body on the attraction layer. In order to rapidly eliminate the electrostatic charge, or to shorten the relaxation time, an electric volume resistivity of a dielectric material constituting the attraction layer has to be below 10.sup.12 .OMEGA.cm.
However, even though the electric volume resistivity of the dielectric material is lowered to shorten the relaxation time and to facilitate detachment of the attracted body from the attraction layer, a problem is encountered in that the electric volume resistivity of the dielectric material can only be reduced to that of the attracted body and the relaxation time can be shortened only within a certain range. This problem results because when the electric volume resistivity of the dielectric material is reduced below that of the attracted body, the potential difference based upon the DC voltage or the voltage equivalent thereto impressed is not created in the attracted body. Thus polarization is not formed and the electrostatic attracting force is not generated between the attraction layer and the attracted body.